The present invention relates to a process for preparing hydrolyzed epoxy resins.
High molecular weight polyepoxide resins have been made more reactive by blending with a hydrolyzed or partially hydrolyzed low molecular weight or high molecular weight epoxy resin as disclosed by Walker in U.S. Pat. No. 3,632,836.
Hydrolyzed and partially hydrolyzed epoxy resins have been prepared by dissolving the epoxy resin to be hydrolyzed in an inert organic solvent, admixing the resultant solution with a dilute aqueous solution of an acid catalyst, heating to a temperature of from about 50.degree. C. to about 374.degree. C., washing to remove the acid catalyst and distilling the solvent to recover the hydrolyzed epoxy resin product. Such process is disclosed by Walker in U.S. Pat. Nos. 3,405,093, 3,632,836 and 3,787,508.
Such process requires the necessity for removing and recovering an organic solvent therefrom, particularly when it is desired to employ the epoxy resins in the high molecular weight form such as in powder coatings, molding powders, epoxy ester resins for coatings, adhesives and the like. The present invention provides a process for preparing high molecular weight epoxy resin compositions containing hydrolyzed epoxy groups during the preparation of the high molecular weight epoxy resin in the absence of an organic solvent. Such a process is obviously desirable from an environmental standpoint.